Saving and retrieving multiple Dictionaries to plist file

So as I am a new to iPhone programming and trying to sort it all out, I have an issue where I'm trying to save a dictionary to a plist in the following format...

-Root
    -StateName (Dictionary)
        - TitleOfLocation (Dictionary)
            -Address (String)
            -City (String)
            -State (String)

Maybe I'm completely off here or the logic needs to be changed, but in the end I need it to populate in a UITableView sorted by the state name.

Currently I can save data to a single dictionary and write it开发者_运维技巧 to a PLST and pull it into a UITableView (the basics, yes i know), but as I said, I am just having issues saving nested Dictionaries.

Would someone be able to guide me the right direction? Thanks.

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You could create nested arrays instead of nested dictionaries. And create another array that holds the name of the state.

- Root (array) 
 - Texas (array) 
  - Location1 (dictionary)
   - TitleOfLocation (string)
   - Address (string)
   - ...
 - Florida (array)
  - Location1 (dictionary)
   - ...
  - Location2 (dictionary)
   - ...
// and
- StateNames (array)
 - Texas (string)
 - Florida (string)

For convenience you could put those two arrays into a single NSDictionary. I didn't do that in my example.
And because NSArray, NSDictionary and NSString all confirm to the NSCoding protocol you can write this dictionary to disk with writeToFile:atomically:

I wrote some sample code for you, because I think the solution is pretty straightforward, but hard to describe with words.

#define kKeyDescription @"kKeyDescription"
#define kKeyAddress     @"kKeyAddress"
#define kKeyCity        @"kKeyCity"
#define kKeyState       @"kKeyState"

- (void)viewDidLoad {
    [super viewDidLoad];
    NSMutableArray *root = [NSMutableArray array];
    NSMutableArray *sectionTitle = [NSMutableArray array];

    NSMutableArray *florida = [NSMutableArray array];
    [root addObject:florida];
    [sectionTitle addObject:@"Florida"];

    NSMutableArray *texas = [NSMutableArray array];
    [root addObject:texas];
    [sectionTitle addObject:@"Texas"];

    NSDictionary *location1 = [NSDictionary dictionaryWithObjectsAndKeys:
                               @"My favorite pizza place", kKeyDescription,
                               @"5106 Grace Drive", kKeyAddress,
                               @"Miami", kKeyCity,
                               @"Florida", kKeyState,
                               nil];
    [florida addObject:location1];

    NSDictionary *location2 = [NSDictionary dictionaryWithObjectsAndKeys:
                               @"Home", kKeyDescription,
                               @"1234 Foobar Street", kKeyAddress,
                               @"Fort Lauderdale", kKeyCity,
                               @"Florida", kKeyState,
                               nil];
    [florida addObject:location2];

    NSDictionary *location3 = [NSDictionary dictionaryWithObjectsAndKeys:
                               @"Franks Workplace", kKeyDescription,
                               @"9101 Baz Avenue", kKeyAddress,
                               @"Houston", kKeyCity,
                               @"Texas", kKeyState,
                               nil];
    [texas addObject:location3];

    data = [root retain];
    sectionData = [sectionTitle retain];
}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return [self.data count];
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
    return [self.sectionData objectAtIndex:section];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return [[self.data objectAtIndex:section] count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSString *cellID = @"MyCellID";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellID];
    if (!cell) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellID] autorelease];
    }
    NSDictionary *object = [[self.data objectAtIndex:indexPath.section] objectAtIndex:indexPath.row];
    //                      < This is the array for the selected state >
    cell.textLabel.text = [object valueForKey:kKeyDescription];
    cell.detailTextLabel.text = [object valueForKey:kKeyAddress];
    return cell;
}